diff --git a/src/server/slavefuncs.c b/src/server/slavefuncs.c
--- a/src/server/slavefuncs.c
+++ b/src/server/slavefuncs.c
@@ -316,12 +316,14 @@ int exec_blender(char *input, char *outp
 
   fprintf(stderr,"Executing: %s\n", frame_str);
   ret = execio_open(&testrem, command, cmd);
-  buf[19] = '\0';
-  while(!execio_read(testrem, buf, 20, &readlen))
+  if(ret)
     {
-      if(readlen > 20) {
-        fprintf(stderr, "Something is terribly wrong!\n");
-       }
+      fprintf(stderr, "error running blender\n");
+      return 1;
+    }
+  buf[19] = '\0';
+  while(!execio_read(testrem, buf, 19, &readlen))
+    {
        buf[readlen] = '\0';
        fprintf(stderr, "read \"%s\"\n", buf);
     }
@@ -818,9 +820,6 @@ int slaveBenchmark(char *datadir, int *b
   buf[19] = '\0';
   while(!execio_read(testrem, buf, 19, &readlen))
     {
-      if(readlen > 20) {
-        fprintf(stderr, "Something is terribly wrong!\n");
-       }
        buf[readlen] = '\0';
        fprintf(stderr, "read \"%s\"\n", buf);
     }